1. Field of the Invention
This invention relates to an integrated support system for supporting sheet metal machining. More particularly, it relates to a sheet metal machining information system adapted to centrally collecting, and reutilizing sheet metal machining data fed back from the shop floor in order to efficiently accumulate and exploit the know-how of skilled operators and simultaneously to shift the operation of arrangements from the actual machining phase to the design phase to improve the quality of sheet metal products and the rate of operation of machine tools.
2. Description of the Related Art
Generally, the sheet metal machining is a two-phased process including a design phase that utilizes CAE (computer aided engineering) in the office and an actual machining phase on the shop floor. The office is provided with CAE equipment (also referred to as automatic programming unit) having CAD/CAM functions, whereas the shop floor is equipped with various machine tools for producing sheet metal products including those for punching, laser machining and bending objects to be machined (hereinafter xe2x80x9cworksxe2x80x9d). The machine tools are controlled by NC data, (i.e., machining programs for controlling the machine tools) prepared in the office by means of the CAE equipment. The CAE equipment and the control terminals of the machine tools are connected with each other by way of private lines.
Now, the conventional procedure of sheet metal machining will be summarily discussed below.
Firstly, the design phase procedure in a manner as described below in terms of reception of a new order.
To begin with, in the design phase, a three faces design drawing is prepared for the ordered product. And the data on the three faces design drawing (FIG. 1(A)) and machining are entered to the CAD equipment. As a result, a development elevation (FIG. 1(B)) is produced to provide reference data for actual machining operations.
More specifically, for preparing a development elevation, the CAD operator has to perform various operations including checking the flanges and other components for interferences, determining the attribute values relating to different machining operations including bending and judging if each of the operations is feasible or not, with confirming the values of the important dimensions in the three face design drawing and with imagining a three-dimensional form of the product on the basis of the drawing. The operation of preparing a development elevation is often referred to as brain development for good reason. Then, pictures will be synthetically produced for the different faces of the product, employing the brain development.
Attribute values will be determined for various different machining operations including bending operations in the synthesizing process. Of the attribute values for the machining operations, the stretch of the work due to a bending operation is typically determined by referring to a table of stretch data stored in the office or the data provided by skilled operators. The bending-related attributes may include the stretch and the angle, the lines and the profiles of the ridges and recesses produced at and around each of the bends of the work.
Then, the CAM apparatus (also referred to as automatic programming unit) assigns arrangement data for producing the product to the development elevation prepared in CAD equipment including data for allocating machine tools and outputs NC data including G codes for controlling the allocated machine tools in the form of perforated tapes. Thus, the NC data prepared in the design phase are selected and finalized on the basis of predetermined standard data and by referring to the data provided by skilled operators. Then comes the machining phase.
Only the NC data including the three faces design drawing and the tapes prepared in the design phase for the sheet metal product are provided for the machining phase along with an letter of machining instruction because the data on the development elevation produced in the design phase are poorly accurate and reliable. Thus, the data on the development elevation are not utilized in the machining phase, so that its not provided for machining site.
In the machining phase, a punching and laser machining step comes first. Arrangements have to be made for the machining phase before actual machining operation. The operation of making arrangements is divided into two major stages. In the first stage of arrangement, the NC tapes are entered and dies are selected and arranged in position, while clamps are aligned and other operations necessary for starting the machining process are performed, the first stage of arrangement is setting operation. In the second stage of arrangement, the NC data produced by the design phase are checked for verification and, if necessary, some of them may have to be modified to meet the requirements specific to the shop floor.
The operation of checking and verifying the NC data is conventionally conducted in an NCT (numerically controlled turret punch press) step (for punching and laser machining operations as an arrangement). And it is necessary to preliminarily perform a test punching and laser machining operation for the verification stage because no data on the development elevation are provided.
After the test punching and laser machining operation, a skilled operator typically performs a series of operations for verifying the NC data including laying a blank (produced by cutting a sheet or a rod of the material to given dimensions so that it may be used for the subsequent operations including bending) on a base sheet (work sheet) and testing if the three faces design drawing can be used to successfully produce a development elevation, using the three faces design drawing and the blank, by way of brain development as in the case of the design phase. Data including the stretch of the work due to a three-dimensional bending operation may have to be appropriately taken into consideration to precisely specify the right spots for piercing. Thus, the provided data have to beverified for the NCT/laser machining step. In other words, with a conventional system, the operation of verifying the data on the development elevation has to be repeated in the machining phase in order to prevent defective development (i.e., a situation where a final product having a desired profile is not obtained).
It is also necessary to make arrangements for a bending operation. More specifically, a skilled operator typically performs a series of operations for verifying the data on the development elevation again by way of brain development, referring to the three faces design drawing on the basis of a three-dimensional image he or she has in the brain and taking the bending sequence into consideration. The arrangements will be finalized by the skilled operator for the bending order (i.e. , bending sequence), the selection of the die to be used for bending and other bending-related operations according to the result of the brain development.
A set of bending-related attributes such as stretch will also have be determined as part of arrangement information. The stretch of a work has to be determined by carefully taking complex factors into consideration, including the wear, the warp and the rate of spring back of the dies on the shop floor. Thus, the bending-related attributes have conventionally been determined on the basis of the know-how of the skilled operators on the shop floor. Then, the parameters such as the L-value and the D-value of the NC data to be used for bending operations are modified, if necessary, to define data for the positional relationship between each die and the work to be machined on the basis of the bending-related attributes and the arrangement data. As used herein, the L-value refers to the distance to be moved for abutment from the center of the die and the D-value refers to the displacement of the die necessary for the bending the work after the work and the die are brought to contact with each other.
The operators on the shop floor then carry out a bending test and other operations and input corrective data through the control terminal of the bending machine to correct the NC data provided by the design site. The corrected NC data are used for actual machining operations on the floor.
As pointed out above, the arrangement data including the selection of dies and the bending order and the bending-related attributes including the stretch of the works are determined on the shop floor on the basis of not only the standard and general attribute values used for the design phase but also the values of the attributes relating to the machine tools and the dies to be used for machining on the floor and other attributes on the site that are specific to the environment of the floor. Then, these values are used to finalize the NC data.
Particularly, in the case of bending a work, the necessary level of precision of punch bending and other bending operations cannot be secured simply by relying on the attribute values (including those for bending) used in the design phase.
Differently stated, the level of machining precision has been maintained and improved by relying on the know-how of skilled operators who are well versed in the conditions of the machine tools and other elements of the shop floor. And the NC data provided by the design phase are modified and finalized by the know-how of skilled operators.
Additionally, the brain development on the shop floor requires the machine tools on the floor to temporarily become down. In other words, the brain development is referred to as intra-operation arrangement and takes a major part of the down time of the machine tools on the shop floor.
At the same time, since the brain development relies solely on human resources, it is inevitably accompanied by potential human errors (e.g., careless errors). Therefore the brain development causes defective development (defective NC machining data and a resultant situation where a final product having a desired profile is not obtained).
Furthermore, the modified and corrected NC machining data are used only for the current machining operations and no means have been provided to store the data. Therefore, if there is an order for a product identical with a past product (hereinafter referred to as repeater), the NC machining data used for the past product are no longer available. The same brain development procedures have to be followed to produce the repeater.
Thus, in short, the above described conventional procedures for sheet metal machining are accompanied by the problems as summarized below.
As pointed out above, the quality of the sheet metal product obtained by sheet metal machining heavily depends on the condition of the machine tools, the environment of the machining operations and other factors on the shop floor especially in sheet metal machining. In other words, reliable data for precision machining cannot be obtained solely from standard attribute values and predicted attribute values acquired by simulation. This is particularly remarkable in the case of bending. Thus, it is absolutely necessary to take the attributes specific to the site of machining including those of the environment into consideration in addition to the standardized attribute values.
Conventionally, however, the site-specific attributes exist only in the brain of skilled operators as a know-how and are used only for correcting the NC machining data in order to adapt the data to the specific requirements of each machining assignment on the shop floor. In other words, the know-how of skilled operators is utilized only on an ad hoc basis not fed back to the design phase and hence the data used to correct the NC machining data fed from the design phase for the specific machining assignment are simply discarded.
Therefore, the data including the development elevation, the various attribute data and the arrangement data (on the bending sequence and the selection of dies) obtained in the design phase remain as standardized data. Differently stated, the data obtained in the design phase shows discrepancies with the corresponding data obtained on the machining site particularly in terms of the site-specific attributes and hence are poorly reliable.
Machining data (NC data) are prepared in the design phase exclusively on the basis of standardized attributes values and fine adjustments necessary for actual machining operations are carried out solely on the machining site.
What is worse, the shop floor responsible for such adjustments are not provided with data obtained in the design phase. As pointed out above, while a development elevation and other data are prepared in the design phase, they are not at all supplied to the shop floor and hence not available on the shop floor.
The only data the shop floor are provided with are NC data that are raw data for controlling the machine tools on the floor, which are scarce in any sense of the word from the viewpoint of accurately and rigorously controlling the machine tools to produce an intended product. Thus, the stretch and the bending-related attributes are finalized by totally relying on the know-how of skilled operators. The development elevation data and the three-dimensional profile of the product are verified on the shop floor by referring to the three faces design drawing fed from the design phase and the outcome of the machining test conducted on the shop floor only to repeatedly follow the verification procedure used for the brain development in the design phase. Additionally, arrangement information for the bending procedure and the selection of dies has to be finalized, taking the site-specific attributes into consideration.
These verification and arrangement operations on the shop floor requires the machine tools on the floor to temporarily halt (become down). In other words, these operations takes a major part of the intra-operation arrangement time which requires the machine tools on the shop floor to halt, so as to reduce the productivity of sheet metal machining.
Finally, the environment of the sheet metal industry will be briefly summarized below. In recent years, orders comes for an increased number of different products to be supplied in small lots and this tendency raises the time spent for the intra-operation arrangement and the inspection to reduce the efficiency of machining. Additionally, as ISO becomes prevalent, more and more rigorous requirements are posed on the quality to further reduce the efficiency. This means that the above described verification and arrangement operation operate as bottle neck for the improvement of the efficiency of sheet metal machining.
In the CAE environment of conventional sheet metal machining, only the NC data obtained in the design phase are provided from the design office to the shop floor for the machine tools there. On the contrary, the operators on the shop floor are alienated from the flow of information. In other words, the design side (office side) and the machining side (shop floor side) are not coordinated in terms of effectively sharing and exploiting machining and machining-related information.
As summarized above, the first problem of the prior art is that the various operations of brain development solely rely on the know-how of few skilled operators on the shop floor and hence the time spent for the brain development and other intra-operation arrangement takes an increasing part in the total machining time on the shop floor and therefore the down time of the machine tools.
The second problem of the prior art is that the site-specific attributes are not fed back to the design phase for the operation of design and verification, which is therefore conducted solely relying on the brain development based on the predicted data obtained by computation. As a result, various shortcomings arise from the brain development particularly in terms of machining and designing (e.g., defects in the development elevation).
The third problem of the prior art lies in that the know-how of skilled operators on the shop floor is not accumulated and stored for utilization so that same NC machining data may have to be prepared for a number of times to increase the cycle time.
These and other problems operate negatively in terms of the rate of operation of machine tools and the quality of produced sheet metal.
This invention is intended to solve the above problems that the various steps of sheet metal machining rely on the know-how of few skilled operators and the intra-operation arrangement time has increased as a result of the increase in the work load of the skilled operators and that the know how of skilled operators are used only on an ad hoc basis and not utilized systematically to make it difficult to maintain and improve the quality of machined sheet metal products.
Therefore, it is an object of the present invention to provide a system for feeding the data obtained on the machining phase back to the design phase to accumulate them and inductively improve the accuracy of the sheet metal machining information by means of the know how of skilled operators on the floor.
Another object of the invention is to provide a system for reducing the work load of skilled operators on the floor and improve the rate of operation of machine tools by shifting the operation of making arrangements from the machining side (the shop floor) to the design side (the office).
Still another object of the invention is to provide a network system adapted to establish and grow a database for storing sheet metal machining information including machining support data so that the stored information may be controlled centrally. Such a system is also adapted to incorporate general purpose machines into the network system so that the data relating to each of the machines in the network system may easily be retrieved by and displayed for the machine operators of the system to support the human on the shop floor as well as the operation of precision design (automatic programming).
The inventor of the present invention has focused his research efforts on realizing a system for accumulating and storing the know how of skilled operators on the shop floor relating to site-specific attributes in order to solve the above problems. In other words, the present invention is intended to provide a system for collecting, accumulating, centrally managing and reutilizing pieces of sheet metal machining information (machining data and machining support data) fed back from the shop floor as site-specific machining data and attribute data in order to minimize the discrepancies between the standard attributes applicable to an ideal environment and the site-specific attributes and also minimize the perception gap between the office and the shop floor to realize a two-way communication between them.
According to a first characteristic aspect of the invention, the above objects are achieved by inductively extracting and generating machining data and machining support data from the attributes specific to the actual machining operations on the shop floor, which data are then fed back to the design side.
More specifically (as shown in FIG. 2), according to the first aspect of the invention, there is provided an integrated support system for supporting sheet metal machining by controlling sheet metal machining data including machining data for controlling machine tools and machining support data relating to the machining data, said system comprising:
component 600 that collects actual machining data for the actual machining process on the shop floor and/or site-specific attribute data on which the actual machining data are based and feeds back as sheet metal machining data; and
component 700 that stores said sheet metal machining data.
The component 600 (actual machining data collecting section) collects and stores NC data modified and added in the course of actual machining process and site-specific attribute data as they are input by floor operators through control terminals.
The component 600 uses the data obtained in the course of actual machining process to affect the component 700 (sheet metal machining data storing means) in terms of modification or addition.
The information obtained in the course of actual machining process preferably refers to corrected final values.
The component 600 may be so arranged that it automatically reads and collects actual machining data 720 and site-specific attribute data 753 obtained in the course of machining a test piece prior to the actual machining process.
With such an configuration, corrective information can be obtained to modify the machining data to reflect the actual shop floor environment.
As shown in FIG. 2, the component 700 (sheet metal machining information storing means) stores machining data (NC data) 720 for controlling the machine tools and machining support data 750 necessary for generating and verifying machining the data.
The machining support data 750 include graphic data 752 and attribute data 753 and may additionally include multimedia data containing image data and sound data.
As shown in FIG. 3, the attribute data 753 include two regions of a standard attribute section 758 for standard and general attributes and a site-specific attribute section 759 obtained on each shop floor.
These regions store attribute data of five different categories necessary and sufficient for sheet metal machining.
Attribute data of five different categories include material attribute data relating to the works to be machined, machine attribute data relating to the machine tools to be used for machining, die attribute data relating to the dies to be used for machining, machining attribute data relating to the actual machining process and environment attribute data relating environmental factors that can affect the machining operations.
With the above configuration, the know-how of skilled sheet metal machining operators that has been used on an ad hoc basis and not exploited for reutilization is collected as actual machining parameters and site-specific attribute values, which are then fed back to the sheet metal machining information storing means 700.
According to a second characteristic aspect of the invention, the sheet metal machining process is simulated to verify the machining data and the machining support data in advance before the actual machining process on the shop floor.
According to the second aspect of the invention, as shown in FIG. 2 there is provided an integrated support system for supporting sheet metal machining comprising:
a design portion A for generating sheet metal machining data 700 including machining data 720 for controlling machine tools and machining support data 750 relating to the machining data; and
machining portion B for performing actual machining operations on the basis of the generated sheet metal machining information 700;
said design portion A including:
component 200 that verifies the profile of the product to be produced by machining and/or the machining sequence on the design site according to the design data and the machining parameters input for the sheet metal product to be produced by machining; wherein said machining data are generated after said verification.
The component 200 (machining simulation component) verifies the profiles of the product to be produced by machining by verifying the input design data and the data on the finished. products (e.g., three-dimensional figure) generated from the design data.
Additionally, the component 200 virtually verifies the machining sequence by forwardly and/or reversely following the actual machining sequence on the CAE equipment, using the data for the finished product.
Such a virtual simulation is preferably conducted by using the attribute data 753 stored in the sheet metal machining information storing means 700.
The method and techniques to be used for the simulation is not limited to the above description.
Preferably, the data on the profile of the product and the data for the finished product include corresponding attribute data added thereto.
With the above configuration, it is possible to provide the shop floor with highly accurate and reliable machining data 720 with related graphic data 752 and attribute data 753.
According to a third characteristic aspect of the invention, an information network is formed to interconnect the machine tools on the shop floor and the design CAE equipment and organize the machine tools of different machining steps by means of the network to make the machining support data available to all of them.
According to the third aspect of the invention, as shown in FIG. 5 there is provided an integrated support system for supporting sheet metal machining comprising:
CAE equipment on the design site;
machine tools 70, 80 on the machining site: and
terminal units 30, 40, 50, 60 connected to the respective machine tools; said terminal units 30, 40, 50, 60 and said CAE equipment 10 being interconnected by the network so as to communicate with each other.
The terminal units 30, 40, 50, 60 and the CAE equipment 10 locally or remotely connected to the network can access to the data storing in the sheet metal machining information storing means 700 by way of a server unit 20. The accessible data include machining data 720 and machining support data 750. The machining support data 750 include graphic data 752 and attribute data 753 and may additionally include multimedia data containing image data and sound data.
With the above configuration, it is possible for the machine tools to carry out high precision machining operations by cross referencing the machining support data 750 (e.g., stretch) including machining data 720 and attribute data 753 relating to the respective machine tools.
The above configuration may be adapted to retrieve data from the sheet metal machining information database 700 generated and accumulated on the design site and edit them instantaneously in a manner of easy input method (e.g., bar code reader on the site).
Thus, with the above configuration, the corrected final values produced on the machining site can be fed back on a real time bases so that the design site and the machining site can enjoy two-way communication.
Various further and more specific objects, features and advantages of the invention will appear from the description give below, taken in connection with the accompanying drawings illustrating by way of example a preferred embodiment of the invention.